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AGPN40 KWNM 250253

Marine Weather Discussion for N Pacific Ocean
NWS Ocean Prediction Center Washington DC
753 PM PDT Wed May 24 2017

.FORECAST DISCUSSION...Major features/winds/seas/significant
.weather for the North Pacific N of 30N and E of 150W.

The most recent ASCAT pass from 19Z shows gale winds across the
inner offshore waters along the northern California coast,
extending into the far SE portion of the Oregon waters. A swath
of 30 kt winds also is shown extending along the Southern coast
of Vancouver island into the Far NE portion of the Washington
waters. The GFS was forecasting winds to increase since that pass
and there could be gales occurring there now. At this time I
don`t plan on making any changes to the current grids or
associated text forecast.


The gale warnings over the central waters will continue through
early Thursday. Latest satellite images still show anticyclonic
circulation west of the northern waters while low clouds cover
the southern waters. The latest observations including
scatterometer pass about 1730Z show maximum winds in gale force
range over the central waters. At 1800Z the NCEP map still has a
broad high pressure with several centers over the eastern and
central pacific ocean. Inland low pressure 1007 MB over northern
California has a cold front stretching southwest across the
southern waters with its trough extending northwest into Oregon
coast. Pressure gradient over the central region is tight but
well relaxed elsewhere. Farther west is area are low pressure
with first center 1012 MB and second 1014 in the sea of Okhotsk.
The second low will move into the Bering sea and develop gale
force winds in its southern sector in the short term.

In the upper levels the models GFS/CMC/UKMETHR/ECMWFHR have
indicated a cut off low with some energy just south of the upper
level ridge that expands north with ridge axis along 145W
longitude. There is some remnant energy from a weakening upper
level trough west of the central waters. In the short term the
models agree on maintaining the upper level high pressure to the
west but weak, with its ridge axis moving east into the forecast
region and that will slacken the pressure gradient over the
central waters. The ridge axis will persist thereafter through
the forecast period.

The models CMC/GFS/ECMWFHR/UKMETHR/NOGAPS have initialized well
the 18z surface observations. The models have also continue with
a general agreement in the short term to weaken the high pressure
west of the region which will result in a relaxed pressure
gradient over the central waters. Will stay with GFS for the
winds with just minor adjustments especially in areas with higher

.SEAS...The seas are small over the southern forecast waters
ranging between 3 and 6 ft. Seas range between 6 and 15 ft over
the north waters. largest seas with peak at 20 ft are over the
central waters. ECMWFWAVE and NWW3 wave models have initialized
well the 18Z observed seas pattern but in areas with maximum
winds the seas are within 2 ft less than the observations. Will
switch to NWW3 in this forecast issuance but modify it slightly
to match the ECMWFWAVE areal coverage especially seas in areas
of higher winds.



.PZ5 Washington/Oregon Waters...
.PZZ800...Inner Waters from Cape Flattery to Cape Shoalwater...
     Gale tonight.
.PZZ815...Inner Waters from Florence OR to Point St. George...
     Gale tonight.

.PZ6 California Waters...
.PZZ820...Inner Waters from Point St. George to Point Arena...
     Gale tonight into Thursday.
.PZZ920...Outer Waters from Point St. George to Point Arena...
     Gale tonight.


.Forecaster Shaw/Musonda. Ocean Prediction Center. is the U.S. government's official web portal to all federal, state and local government web resources and services.